1.\" Copyright (c) 1997 Peter Wemm <[email protected]> 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 12.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 13.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 14.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 15.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 16.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 17.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 18.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 19.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 20.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 21.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 22.\" SUCH DAMAGE. 23.\" 24.\" $FreeBSD$ 25.\" 26.Dd August 19, 1997 27.Dt GETSID 2 28.Os 29.Sh NAME 30.Nm getsid 31.Nd get process session 32.Sh LIBRARY 33.Lb libc 34.Sh SYNOPSIS 35.Fd #include <unistd.h> 36.Ft pid_t 37.Fn getsid "pid_t pid" 38.Sh DESCRIPTION 39The session ID of the process identified by 40.Fa pid 41is returned by 42.Fn getsid . 43If 44.Fa pid 45is zero, 46.Fn getsid 47returns the session ID of the current process. 48.Sh RETURN VALUES 49Upon successful completion, the function 50.Fn getsid 51returns the session ID of 52the specified process; otherwise, it returns a value of -1 and 53sets errno to indicate an error. 54.Sh ERRORS 55.Fn getsid 56will succeed unless: 57.Bl -tag -width Er 58.It Bq Er ESRCH 59if there is no process with a process ID equal to 60.Fa pid . 61.El 62.Pp 63Note that an implementation may restrict this function call to 64processes within the same session ID as the calling process. 65.Sh SEE ALSO 66.Xr getpgid 2 , 67.Xr getpgrp 2 , 68.Xr setpgid 2 , 69.Xr setsid 2 , 70.Xr termios 4 71.Sh HISTORY 72The 73.Fn getsid 74function call appeared in 75.Fx 3.0 . 76The 77.Fn getsid 78function call is derived from its usage in 79.At V . 80